The semiconductor device in an integrated circuit, especially in an ultra-large scale integrated circuit, includes a metal-oxide-semiconductor field effect transistor (MOSFET). With continuous development of integrated circuit manufacturing technology, process node of the semiconductor device continues to decrease, and geometric dimensions of the semiconductor device continue to shrink following Moore's law. When the size of the semiconductor device is reduced to a certain extent, various secondary effects caused by physical limit of the semiconductor device have been emerged, and feature dimensions of the semiconductor device become more and more difficult to scale down. Among them, in the field of semiconductor manufacturing, how to solve a large leakage current issue of the semiconductor device is most challenging. The large leakage current of the semiconductor device is mainly caused by the continuous decreasing of the thickness of a conventional gate dielectric layer.
Currently, a high-K gate dielectric material is used to replace the conventional silicon dioxide gate dielectric material, and a metal material is used as a gate electrode to avoid a Fermi level pinning effect between the high-K material and a conventional gate electrode material as well as a boron permeation effect. The use of the high-K material and the metal gate reduces the leakage current of the semiconductor device.
Although the use of the high-K material and the metal gate can improve the electrical performance of the semiconductor device to a certain extent, the electrical performance and yield of the conventional semiconductor device still need to be improved. The disclosed device structures and methods are directed to solve one or more problems set forth above and other problems in the art.